<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Cache
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Cache.php 18951 2009-11-12 16:26:19Z alexander $
 */


/**
 * @package    Zend_Cache
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Cache
{

	/**
	 * Standard frontends
	 *
	 * @var array
	 */
	public static $standardFrontends = array('Core', 'Output', 'Class', 'File', 'Function', 'Page');

	/**
	 * Standard backends
	 *
	 * @var array
	 */
	public static $standardBackends = array('File', 'Sqlite', 'Memcached', 'Apc', 'ZendPlatform', 'Xcache', 'TwoLevels');

	/**
	 * Standard backends which implement the ExtendedInterface
	 *
	 * @var array
	 */
	public static $standardExtendedBackends = array('File', 'Apc', 'TwoLevels', 'Memcached', 'Sqlite');

	/**
	 * Only for backward compatibily (may be removed in next major release)
	 *
	 * @var array
	 * @deprecated
	 */
	public static $availableFrontends = array('Core', 'Output', 'Class', 'File', 'Function', 'Page');

	/**
	 * Only for backward compatibily (may be removed in next major release)
	 *
	 * @var array
	 * @deprecated
	 */
	public static $availableBackends = array('File', 'Sqlite', 'Memcached', 'Apc', 'ZendPlatform', 'Xcache', 'TwoLevels');

	/**
	 * Consts for clean() method
	 */
	const CLEANING_MODE_ALL              = 'all';
	const CLEANING_MODE_OLD              = 'old';
	const CLEANING_MODE_MATCHING_TAG     = 'matchingTag';
	const CLEANING_MODE_NOT_MATCHING_TAG = 'notMatchingTag';
	const CLEANING_MODE_MATCHING_ANY_TAG = 'matchingAnyTag';

	/**
	 * Factory
	 *
	 * @param mixed  $frontend        frontend name (string) or Zend_Cache_Frontend_ object
	 * @param mixed  $backend         backend name (string) or Zend_Cache_Backend_ object
	 * @param array  $frontendOptions associative array of options for the corresponding frontend constructor
	 * @param array  $backendOptions  associative array of options for the corresponding backend constructor
	 * @param boolean $customFrontendNaming if true, the frontend argument is used as a complete class name ; if false, the frontend argument is used as the end of "Zend_Cache_Frontend_[...]" class name
	 * @param boolean $customBackendNaming if true, the backend argument is used as a complete class name ; if false, the backend argument is used as the end of "Zend_Cache_Backend_[...]" class name
	 * @param boolean $autoload if true, there will no require_once for backend and frontend (usefull only for custom backends/frontends)
	 * @throws Zend_Cache_Exception
	 * @return Zend_Cache_Core|Zend_Cache_Frontend
	 */
	public static function factory($frontend, $backend, $frontendOptions = array(), $backendOptions = array(), $customFrontendNaming = false, $customBackendNaming = false, $autoload = false)
	{
		if (is_string($backend)) {
			$backendObject = self::_makeBackend($backend, $backendOptions, $customBackendNaming, $autoload);
		} else {
			if ((is_object($backend)) && (in_array('Zend_Cache_Backend_Interface', class_implements($backend)))) {
				$backendObject = $backend;
			} else {
				self::throwException('backend must be a backend name (string) or an object which implements Zend_Cache_Backend_Interface');
			}
		}
		if (is_string($frontend)) {
			$frontendObject = self::_makeFrontend($frontend, $frontendOptions, $customFrontendNaming, $autoload);
		} else {
			if (is_object($frontend)) {
				$frontendObject = $frontend;
			} else {
				self::throwException('frontend must be a frontend name (string) or an object');
			}
		}
		$frontendObject->setBackend($backendObject);
		return $frontendObject;
	}

	/**
	 * Frontend Constructor
	 *
	 * @param string  $backend
	 * @param array   $backendOptions
	 * @param boolean $customBackendNaming
	 * @param boolean $autoload
	 * @return Zend_Cache_Backend
	 */
	public static function _makeBackend($backend, $backendOptions, $customBackendNaming = false, $autoload = false)
	{
		if (!$customBackendNaming) {
			$backend  = self::_normalizeName($backend);
		}
		if (in_array($backend, Zend_Cache::$standardBackends)) {
			// we use a standard backend
			$backendClass = 'Zend_Cache_Backend_' . $backend;
			// security controls are explicit
			require_once str_replace('_', DIRECTORY_SEPARATOR, $backendClass) . '.php';
		} else {
			// we use a custom backend
			if (!preg_match('~^[\w]+$~D', $backend)) {
				Zend_Cache::throwException("Invalid backend name [$backend]");
			}
			if (!$customBackendNaming) {
				// we use this boolean to avoid an API break
				$backendClass = 'Zend_Cache_Backend_' . $backend;
			} else {
				$backendClass = $backend;
			}
			if (!$autoload) {
				$file = str_replace('_', DIRECTORY_SEPARATOR, $backendClass) . '.php';
				if (!(self::_isReadable($file))) {
					self::throwException("file $file not found in include_path");
				}
				require_once $file;
			}
		}
		return new $backendClass($backendOptions);
	}

	/**
	 * Backend Constructor
	 *
	 * @param string  $frontend
	 * @param array   $frontendOptions
	 * @param boolean $customFrontendNaming
	 * @param boolean $autoload
	 * @return Zend_Cache_Core|Zend_Cache_Frontend
	 */
	public static function _makeFrontend($frontend, $frontendOptions = array(), $customFrontendNaming = false, $autoload = false)
	{
		if (!$customFrontendNaming) {
			$frontend = self::_normalizeName($frontend);
		}
		if (in_array($frontend, self::$standardFrontends)) {
			// we use a standard frontend
			// For perfs reasons, with frontend == 'Core', we can interact with the Core itself
			$frontendClass = 'Zend_Cache_' . ($frontend != 'Core' ? 'Frontend_' : '') . $frontend;
			// security controls are explicit
			require_once str_replace('_', DIRECTORY_SEPARATOR, $frontendClass) . '.php';
		} else {
			// we use a custom frontend
			if (!preg_match('~^[\w]+$~D', $frontend)) {
				Zend_Cache::throwException("Invalid frontend name [$frontend]");
			}
			if (!$customFrontendNaming) {
				// we use this boolean to avoid an API break
				$frontendClass = 'Zend_Cache_Frontend_' . $frontend;
			} else {
				$frontendClass = $frontend;
			}
			if (!$autoload) {
				$file = str_replace('_', DIRECTORY_SEPARATOR, $frontendClass) . '.php';
				if (!(self::_isReadable($file))) {
					self::throwException("file $file not found in include_path");
				}
				require_once $file;
			}
		}
		return new $frontendClass($frontendOptions);
	}

	/**
	 * Throw an exception
	 *
	 * Note : for perf reasons, the "load" of Zend/Cache/Exception is dynamic
	 * @param  string $msg  Message for the exception
	 * @throws Zend_Cache_Exception
	 */
	public static function throwException($msg)
	{
		// For perfs reasons, we use this dynamic inclusion
		require_once 'Zend/Cache/Exception.php';
		throw new Zend_Cache_Exception($msg);
	}

	/**
	 * Normalize frontend and backend names to allow multiple words TitleCased
	 *
	 * @param  string $name  Name to normalize
	 * @return string
	 */
	protected static function _normalizeName($name)
	{
		$name = ucfirst(strtolower($name));
		$name = str_replace(array('-', '_', '.'), ' ', $name);
		$name = ucwords($name);
		$name = str_replace(' ', '', $name);
		return $name;
	}

	/**
	 * Returns TRUE if the $filename is readable, or FALSE otherwise.
	 * This function uses the PHP include_path, where PHP's is_readable()
	 * does not.
	 *
	 * Note : this method comes from Zend_Loader (see #ZF-2891 for details)
	 *
	 * @param string   $filename
	 * @return boolean
	 */
	private static function _isReadable($filename)
	{
		if (!$fh = @fopen($filename, 'r', true)) {
			return false;
		}
		@fclose($fh);
		return true;
	}

}
